Core A will continue to provide standardized procedures for the quantitative study of processes relevant to thrombus formation and regulation using In vivo models in the murine circulation and ex vivo models in perfusion chambers under the influence of defined flow forces. Core A will also perform isolation, culture and characterization of relevant vascular cells. Project 1 (Griffin;39% use) will utilize primarily in vivo models to study the antithrombotic properties of wild type and mutant activated protein C and protein S. Project 2 (Ginsberg;22% use) will utilize in vivo models to study the arterial thrombogenic phenotype resulting from functional alterations of CD98, as well as ex vivo models to study the thrombogenic potential of smooth muscle cells derived from the same mutant mice. Project 3 (Ruf;39% use) will utilize in vivo models of response to vascular injury to explore the mechanisms leading to the induction of tissue factor activity, as well as complementary ex vivo fiow models to explore the mechanisms of tissue factor decryption in relevant vascular cells under more constrained experimental conditions.